The invention relates generally to the field of data storage in computer systems and, more specifically, to a technique for updating elements in a multi-server data storage facility using a state machine.
Storage facilities such as storage servers as commonly used by corporations and other organizations have high-capacity disk arrays to store large amounts of data from external host systems. A storage facility may also backup data from another storage facility, such as at a remote site. The IBM® Enterprise Storage Server (ESS) is an example of such a storage facility. Such facilities can access arrays of disks or other storage media to store and retrieve data. Moreover, redundant capabilities may be provided as a further safeguard against data loss. For example, a dual server system includes two separate servers that can access the same storage disks.
Moreover, storage facilities include several subsystems and components, referred to as updateable elements, each requiring its own unique update image and update commands. The elements are updated from time to time to provide new features or fix problems, for instance. Elements that may be updated include host adapters, device adapters, service processors, storage disks, power components, and so forth.
However, there is a need for greater flexibility in the update process, particularly when the update process is carried out using a fixed state machine.